package com.fenghongzhang.sample.extendmethod

fun main() {
    val s = "aa"
//    s.countletters()
//    println(s.toUpper())
//    println(s.toUpperCase())
//    val plus = s+"12"
//    println(plus)
//    println(s * 3)
    val money = Money(2)
    val mone1 = Money(3)+money
    print(mone1)
}